Mobile devices (e.g., mobile phones, etc.) can include various accessories. For example, mobile devices with audio jacks can be configured to be coupled to a headset having at least one of a headphone, a speaker, a microphone, or a send/end key. In an example, the mobile device can include a comparator configured to identify when the send/end key is activated on the headset. In certain examples, activating the send/end key can reduce the microphone bias to ground or increase the microphone bias to a full microphone bias voltage level. In an example, a voltage divider can be used to set the comparator threshold level to identify the send/end key activation. In many devices, the resistors used for the voltage divider are connected to a supply that is normally enabled, even if the headset is not connected, creating excess current draw.